Improvement in processes of ivianufacturing iviiddlings-flour



L. DOWNTON.

P r o c e s s 0 f M a n u fa c t u r i n g M i d d l i n g s F I u u r'.No.162/157.

Patented April 20, 1875.

ROBERT L. DOWNTON, OF ST. LOUIS, MISSOURI.

IMPROVEMENT IN PROCESSES OF MANUFACTURlNG MIDDLlNGS-FLOUR.

Specification forming part of Letters Patent No. 162, 557, dated April20, 1875; application filed March 29, 1875.

To all whom it may concern:

Be it known that I, ROBERT L. DOWNTON, of the city and county of St.Louis, in the State of Missouri, have invented a new and usefulImprovement in the Process of Manufacturing llIiddlings-Flour, of whichthe following is a specification:

This invention has for its aim the better working or manipulating ofgrain particles known as middlings for their reduction into meal orflour.

To fully set forth the advantages that this process possesses over anyof the various processes previously known and in use, it will benecessary to briefly describe the manufacture as now practiced.

It is customary under the ordinary mode of milling to separate andpurify the middlings by the action of air alone, or air and boltingclothcombined; then to convey the purified product to millstones to be groundto a sufficient fineness to admit of the passage of the middlings-flourthrough the meshes of the bolting-cloth, which is used as a finishingpreparer between the stones and the fiour barrels. or sacks receivingthe finished product. In some cases the middlings that are notsufiiciently reduced to go through the meshes of the cloth pass throughthe ends of the flour-bolts, and are brought back onto some of thevarious purifiers and subjected to repurification. This process requiresmuch careful manipulation, and even then the yellow germ and pellicle ofthe grain will be so torn and pulverized by the stones that looseportions of the same will pass through the meshes of the boltingclothinto the flour with injurious effect. The reason why the germ andpellicle is so torn is, that millstones are composed of two disks--onerevolving, the other stationaryreceivin g the material to be ground atthe eye or center of the stones, and compelling it by centrifugal forceto escape at the skirt or periphery of the stones, passing alternatelyover face and furrow until it reaches the periphery, where it isdischarged. Such action comminutes the germs and forms specks thatcannot be removed by the purifiers, and are therefore ground in with theflour.

In the manufacture of middlings-flour the action of stones on themiddlings is not different from their action on grain, but in thewheat-stones the germ ends and bran are not sufficiently comminuted byone grinding to pass through the meshes of the cloth used for the flourknown to the trade as first run. I purpose to arrest and remove suchgerm mat ter and bran particles by my improved process before they reachthe second grind on the middlings-stones by placing between thepurifiers or separators and middlings-stones one or more sets of rolls,which will operate to reduce the large middlings by a bruising orcrushing action, while they simply flatten out the intermixed germs andbran. Any of the various purifiers or separators in public use may beemployed. A-second important advantage or result of this improvedprocess is the production of a large yield of highgrade flour. The largemiddlin gs or glutinous particles of the grain require more grindingthan do the finer and more starchy particles removed at the head orfirst part of the purifiers; and when ground together, as is generallythe case with small mills, and frequently the case with large mills, themeal is considerably heated in the grinding, owing to the millersrequiring the middlings-meal to be of uniform fineness. The dispositionand fineness of the small middlings cause them to flour quicker than thelarge middlings, therefore the grinding is unequal, as, in order for thelarge glutinous middlings to be ground enough, the small starchmiddlings must be ground too much. This impairs the quality of the flourby deadening it as well as by reducing the germs and bran to such anextent as to cause them to pass through the cloth. Some mills,therefore, run the coarsest middlings to a lower grade of flour.

It is plain that, with an intermediate reduction, by theflattening-rolls working on the large middlings, as above set forth, thecomminution of the middlings under the stones is rendered more equal anda larger percentage of high-grade flour can be made.

I will now describe briefly my mode of milling, referring, forillustrations, to the accompanying drawing, in which- Figure l is ageneral side view, partly in section, showing an apparatus or a seriesof machines comprising a section of my purifier A; and Fig. 2 is a likeView of the same apparatus, in part, illustrating the employment of anyother purifier A Naturally the germs and bran are kept with the largeand valuable middliugs or particles of grain by the bolting-cloth of thepurifyingmachines or flour-bolts till they reach certain parts, wherethe middlings are subjected to strong currents of air to remove lightbranflakes and fuzzy matter. The partially-freed middlin gs are nowpassed from the purifier A or A between rolls or uniformly-rotatingsurfaces B, where the good middlings particles, being more brittle, arereduced to small granules or to flour, while the germ and heavy branmatter, being of a soft plastic nature, is flattened out, so that, onpassing it into a reciprocating or revolving bolt, (J, clothed withsuitable cloth, the fiouring matter is thoroughly removed through themeshes of the cloth in a,

BOBEET L. DOWNTON.

Witnesses:

J AS. L. EWIN, WALTER ALLEN.

